With the rapid growth of wireless access networks, the great advances in mobile computing, and the overwhelming success of the Internet, a new communication paradigm has emerged, whereby mobile users require ubiquitous access to their services while roaming, preferably without interruption or degradation of their communication quality. One of the research challenges for next generation (NG) all-IP-based wireless and mobile systems is the design of intelligent mobility management techniques that take advantage of IP-based technologies to achieve global roaming among heterogeneous access technologies [1].